/*
 * Copyright 2008 The Apache Software Foundation Licensed under the Apache
 * License, Version 2.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law
 * or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

package org.apache.ibatis.ibator.plugins;

import java.util.Iterator;
import java.util.List;

import org.apache.ibatis.ibator.api.IbatorPluginAdapter;
import org.apache.ibatis.ibator.api.IntrospectedColumn;
import org.apache.ibatis.ibator.api.IntrospectedTable;
import org.apache.ibatis.ibator.api.dom.OutputUtilities;
import org.apache.ibatis.ibator.api.dom.java.FullyQualifiedJavaType;
import org.apache.ibatis.ibator.api.dom.java.JavaVisibility;
import org.apache.ibatis.ibator.api.dom.java.Method;
import org.apache.ibatis.ibator.api.dom.java.Parameter;
import org.apache.ibatis.ibator.api.dom.java.TopLevelClass;
import org.apache.ibatis.ibator.internal.util.JavaBeansUtil;

/**
 * This plugin adds equals() and hashCode() methods to the generated model
 * classes. It demonstrates the process of adding methods to generated classes
 * <p>
 * The <tt>equals</tt> method generated by this class is correct in most cases,
 * but will probably NOT be correct if you have specified a rootClass - because
 * our equals method only checks the fields it knows about.
 * <p>
 * Similarly, the <tt>hashCode</tt> method generated by this class only relies
 * on fields it knows about. Anything you add, or fields in a super class will
 * not be factored into the hash code.
 * 
 * @author Jeff Butler
 */
public class EqualsHashCodePlugin extends IbatorPluginAdapter
{

	public EqualsHashCodePlugin()
	{
	}

	/**
	 * This plugin is always valid - no properties are required
	 */
	public boolean validate(List<String> warnings)
	{
		return true;
	}

	@Override
	public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass,
			IntrospectedTable introspectedTable)
	{
		List<IntrospectedColumn> columns;
		if (introspectedTable.getRules().generateRecordWithBLOBsClass())
		{
			columns = introspectedTable.getNonBLOBColumns();
		}
		else
		{
			columns = introspectedTable.getAllColumns();
		}

		generateEquals(topLevelClass, columns, introspectedTable);
		generateHashCode(topLevelClass, columns, introspectedTable);

		return true;
	}

	@Override
	public boolean modelPrimaryKeyClassGenerated(TopLevelClass topLevelClass,
			IntrospectedTable introspectedTable)
	{
		generateEquals(topLevelClass, introspectedTable.getPrimaryKeyColumns(),
				introspectedTable);
		generateHashCode(topLevelClass,
				introspectedTable.getPrimaryKeyColumns(), introspectedTable);

		return true;
	}

	@Override
	public boolean modelRecordWithBLOBsClassGenerated(
			TopLevelClass topLevelClass, IntrospectedTable introspectedTable)
	{
		generateEquals(topLevelClass, introspectedTable.getAllColumns(),
				introspectedTable);
		generateHashCode(topLevelClass, introspectedTable.getAllColumns(),
				introspectedTable);

		return true;
	}

	/**
	 * Generates an <tt>equals</tt> method that does a comparison of all fields.
	 * <p>
	 * The generated <tt>equals</tt> method will be correct unless:
	 * <ul>
	 * <li>Other fields have been added to the Ibator generated classes</li>
	 * <li>A <tt>rootClass</tt> is specified that holds state</li>
	 * </ul>
	 * 
	 * @param topLevelClass
	 *            the class to which the method will be added
	 * @param introspectedColumns
	 *            column definitions of this class and any superclass of this
	 *            class
	 * @param introspectedTable
	 *            the table corresponding to this class
	 */
	protected void generateEquals(TopLevelClass topLevelClass,
			List<IntrospectedColumn> introspectedColumns,
			IntrospectedTable introspectedTable)
	{
		Method method = new Method();
		method.setVisibility(JavaVisibility.PUBLIC);
		method.setReturnType(FullyQualifiedJavaType
				.getBooleanPrimitiveInstance());
		method.setName("equals"); //$NON-NLS-1$
		method.addParameter(new Parameter(FullyQualifiedJavaType
				.getObjectInstance(), "that")); //$NON-NLS-1$
		if (introspectedTable.isJava5Targeted())
		{
			method.addAnnotation("@Override"); //$NON-NLS-1$
		}

		ibatorContext.getCommentGenerator().addGeneralMethodComment(method,
				introspectedTable);

		method.addBodyLine("if (this == that) {"); //$NON-NLS-1$
		method.addBodyLine("return true;"); //$NON-NLS-1$
		method.addBodyLine("}"); //$NON-NLS-1$

		method.addBodyLine("if (that == null) {"); //$NON-NLS-1$
		method.addBodyLine("return false;"); //$NON-NLS-1$
		method.addBodyLine("}"); //$NON-NLS-1$

		method.addBodyLine("if (getClass() != that.getClass()) {"); //$NON-NLS-1$
		method.addBodyLine("return false;"); //$NON-NLS-1$
		method.addBodyLine("}"); //$NON-NLS-1$

		StringBuilder sb = new StringBuilder();
		sb.append(topLevelClass.getType().getShortName());
		sb.append(" other = ("); //$NON-NLS-1$
		sb.append(topLevelClass.getType().getShortName());
		sb.append(") that;"); //$NON-NLS-1$
		method.addBodyLine(sb.toString());

		boolean first = true;
		Iterator<IntrospectedColumn> iter = introspectedColumns.iterator();
		while (iter.hasNext())
		{
			IntrospectedColumn introspectedColumn = iter.next();

			sb.setLength(0);

			if (first)
			{
				sb.append("return ("); //$NON-NLS-1$
				first = false;
			}
			else
			{
				OutputUtilities.javaIndent(sb, 1);
				sb.append("&& ("); //$NON-NLS-1$
			}

			String getterMethod = JavaBeansUtil.getGetterMethodName(
					introspectedColumn.getJavaProperty(),
					introspectedColumn.getFullyQualifiedJavaType());

			if (introspectedColumn.getFullyQualifiedJavaType().isPrimitive())
			{
				sb.append("this."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == "); //$NON-NLS-1$
				sb.append("other."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("())"); //$NON-NLS-1$
			}
			else
			{
				sb.append("this."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == null ? other."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == null : this."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("().equals(other."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("()))"); //$NON-NLS-1$
			}

			if (!iter.hasNext())
			{
				sb.append(';');
			}

			method.addBodyLine(sb.toString());
		}

		topLevelClass.addMethod(method);
	}

	/**
	 * Generates a <tt>hashCode</tt> method that includes all fields.
	 * <p>
	 * Note that this implementation is based on the eclipse foundation hashCode
	 * generator.
	 * 
	 * @param topLevelClass
	 *            the class to which the method will be added
	 * @param introspectedColumns
	 *            column definitions of this class and any superclass of this
	 *            class
	 * @param introspectedTable
	 *            the table corresponding to this class
	 */
	protected void generateHashCode(TopLevelClass topLevelClass,
			List<IntrospectedColumn> introspectedColumns,
			IntrospectedTable introspectedTable)
	{
		Method method = new Method();
		method.setVisibility(JavaVisibility.PUBLIC);
		method.setReturnType(FullyQualifiedJavaType.getIntInstance());
		method.setName("hashCode"); //$NON-NLS-1$
		if (introspectedTable.isJava5Targeted())
		{
			method.addAnnotation("@Override"); //$NON-NLS-1$
		}

		ibatorContext.getCommentGenerator().addGeneralMethodComment(method,
				introspectedTable);

		method.addBodyLine("final int prime = 31;"); //$NON-NLS-1$
		method.addBodyLine("int result = 1;"); //$NON-NLS-1$

		StringBuilder sb = new StringBuilder();
		boolean hasTemp = false;
		Iterator<IntrospectedColumn> iter = introspectedColumns.iterator();
		while (iter.hasNext())
		{
			IntrospectedColumn introspectedColumn = iter.next();

			FullyQualifiedJavaType fqjt = introspectedColumn
					.getFullyQualifiedJavaType();

			String getterMethod = JavaBeansUtil.getGetterMethodName(
					introspectedColumn.getJavaProperty(), fqjt);

			sb.setLength(0);
			if (fqjt.isPrimitive())
			{
				if ("boolean".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + ("); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("() ? 1231 : 1237);"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				}
				else
					if ("byte".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
						sb.append("result = prime * result + "); //$NON-NLS-1$
						sb.append(getterMethod);
						sb.append("();"); //$NON-NLS-1$
						method.addBodyLine(sb.toString());
					}
					else
						if ("char".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
							sb.append("result = prime * result + "); //$NON-NLS-1$
							sb.append(getterMethod);
							sb.append("();"); //$NON-NLS-1$
							method.addBodyLine(sb.toString());
						}
						else
							if ("double".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
								if (!hasTemp)
								{
									method.addBodyLine("long temp;"); //$NON-NLS-1$
									hasTemp = true;
								}
								sb.append("temp = Double.doubleToLongBits("); //$NON-NLS-1$
								sb.append(getterMethod);
								sb.append("());"); //$NON-NLS-1$
								method.addBodyLine(sb.toString());
								method.addBodyLine("result = prime * result + (int) (temp ^ (temp >>> 32));"); //$NON-NLS-1$
							}
							else
								if ("float".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
									sb.append("result = prime * result + Float.floatToIntBits("); //$NON-NLS-1$
									sb.append(getterMethod);
									sb.append("());"); //$NON-NLS-1$
									method.addBodyLine(sb.toString());
								}
								else
									if ("int".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
										sb.append("result = prime * result + "); //$NON-NLS-1$
										sb.append(getterMethod);
										sb.append("();"); //$NON-NLS-1$
										method.addBodyLine(sb.toString());
									}
									else
										if ("long".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
											sb.append("result = prime * result + (int) ("); //$NON-NLS-1$
											sb.append(getterMethod);
											sb.append("() ^ ("); //$NON-NLS-1$
											sb.append(getterMethod);
											sb.append("() >>> 32));"); //$NON-NLS-1$
											method.addBodyLine(sb.toString());
										}
										else
											if ("short".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
												sb.append("result = prime * result + "); //$NON-NLS-1$
												sb.append(getterMethod);
												sb.append("();"); //$NON-NLS-1$
												method.addBodyLine(sb
														.toString());
											}
											else
											{
												// should never happen
												continue;
											}
			}
			else
			{
				sb.append("result = prime * result + (("); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == null) ? 0 : "); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("().hashCode());"); //$NON-NLS-1$
				method.addBodyLine(sb.toString());
			}
		}

		method.addBodyLine("return result;"); //$NON-NLS-1$

		topLevelClass.addMethod(method);
	}
}
